diff --git a/scripts/ci/classify_failures.py b/scripts/ci/classify_failures.py
index 8d3141ab89ca..93ff33ada1a4 100644
--- a/scripts/ci/classify_failures.py
+++ b/scripts/ci/classify_failures.py
@@ -97,6 +97,9 @@ def sig(name: str, verdict: str, pattern: str, why: str) -> Signature:
         "the compiled app-host products did not restore on this runner"),
     sig("app-host-preparation", MACHINE, r"Unexpected app-host preparation outcome",
         "the isolated app-host home was not prepared"),
+    sig("gui-token-unavailable", MACHINE,
+        r"^Could not take this Mac's gui token for the app-host tests \(take-gui exited ",
+        "the runner could not acquire the GUI token for app-host tests"),
     # The CLI and the package framework it links came from different builds:
     # the runner staged products from another job. Compiled together, they match.
     sig("mixed-products", MACHINE, r"dyld\[\d+\]: Symbol not found: ",
diff --git a/tests/test_ci_classify_failures.py b/tests/test_ci_classify_failures.py
index 611c9f2ae790..5621f8c5fa01 100644
--- a/tests/test_ci_classify_failures.py
+++ b/tests/test_ci_classify_failures.py
@@ -62,6 +62,12 @@
     2026-09-27T09:31:30.4083830Z ##[error]Process completed with exit code 65.
     """)
 
+NO_CONSOLE_WARNING = (
+    "No logged-in console user (or no passwordless sudo) on this runner; running in the current bootstrap. "
+    "XCTest will fail here if this runner has no GUI session."
+)
+GUI_TOKEN_UNAVAILABLE = "Could not take this Mac's gui token for the app-host tests (take-gui exited 1)."
+
 PARAMETERIZED_TEST_FAILED = (
     "2026-09-27T10:40:00.0000000Z ✘ Test mapsConnectionClosedStartupFailureToRetryableStatus(_:) recorded an issue "
     "with 1 argument diagnostic → \"Connection closed by 192.0.2.1 port 22\" at "
@@ -112,6 +118,31 @@ def test_products_from_two_builds_outweigh_the_test_failures_they_cause(self) ->
         self.assertEqual((verdict, signature), (cf.MACHINE, "mixed-products"))
         self.assertIn("Symbol not found", cf.classify_text(MIXED_PRODUCTS)["evidence"])
 
+    def test_a_gui_token_failure_is_the_machine(self) -> None:
+        log = f"##[error]{GUI_TOKEN_UNAVAILABLE}\n"
+        self.assertEqual(self.verdict(log), (cf.MACHINE, "gui-token-unavailable"))
+        self.assertIn(GUI_TOKEN_UNAVAILABLE, cf.classify_text(log)["evidence"])
+
+    def test_a_gui_token_failure_is_read_from_its_failure_annotation(self) -> None:
+        result = cf.classify_text("", [GUI_TOKEN_UNAVAILABLE])
+        self.assertEqual((result["verdict"], result["signature"]), (cf.MACHINE, "gui-token-unavailable"))
+
+    def test_an_ambiguous_console_warning_does_not_outweigh_test_failures(self) -> None:
+        log = f"##[warning]{NO_CONSOLE_WARNING}\n{TEST_FAILED}"
+        self.assertEqual(self.verdict(log), (cf.CODE, "swift-testing-issue"))
+
+    def test_a_gui_token_diagnostic_in_assertion_output_is_the_code(self) -> None:
+        log = ("✘ Test reportsGUITokenFailure() recorded an issue at GUITokenTests.swift:12:5: "
+               f'Expectation failed: diagnostic → "{GUI_TOKEN_UNAVAILABLE}"\n'
+               "##[error]Process completed with exit code 1.\n")
+        self.assertEqual(self.verdict(log), (cf.CODE, "swift-testing-issue"))
+
+    def test_an_echoed_gui_token_error_does_not_outweigh_test_failures(self) -> None:
+        log = ('##[group]Run "$helper" take-gui --wait 1800\n'
+               f'{ESC}[36;1mecho "::error::{GUI_TOKEN_UNAVAILABLE}"{ESC}[0m\n'
+               f"##[endgroup]\n{TEST_FAILED}")
+        self.assertEqual(self.verdict(log), (cf.CODE, "swift-testing-issue"))
+
     def test_a_test_failure_on_a_healthy_runner_is_the_code(self) -> None:
         self.assertEqual(self.verdict(TEST_FAILED), (cf.CODE, "swift-testing-issue"))
         self.assertEqual(self.verdict(PARAMETERIZED_TEST_FAILED), (cf.CODE, "swift-testing-issue"))
@@ -144,6 +175,8 @@ def test_a_machine_line_in_a_step_that_passed_does_not_count(self) -> None:
             2026-09-27T10:00:03.0Z Warning: Failed to save: No space left on device
             """)
         self.assertEqual(self.verdict(log), (cf.CODE, "swift-testing-issue"))
+        gui_token_noise = log.replace("Warning: Failed to save: No space left on device", GUI_TOKEN_UNAVAILABLE)
+        self.assertEqual(self.verdict(gui_token_noise), (cf.CODE, "swift-testing-issue"))
 
     def test_a_group_a_step_titles_run_keeps_its_output(self) -> None:
         log = textwrap.dedent("""\
@@ -203,6 +236,14 @@ def test_every_failure_on_the_machine_reruns(self) -> None:
         self.assertTrue(rerun)
         self.assertIn("attempt 2", line)
 
+    def test_a_gui_token_failure_does_not_block_other_machine_retries(self) -> None:
+        report = self.report([])
+        report["jobs"] = cf.classify_jobs(
+            [job(1, "macos / app-host unit tests (2/7)"), job(2, "macos / swift-package-tests")],
+            {1: (f"##[error]{GUI_TOKEN_UNAVAILABLE}\n", []), 2: (HOOK_REFUSED, [])},
+        )
+        self.assertTrue(cf.rerun_decision(report, self.LATEST)[0])
+
     def test_one_code_or_unknown_failure_keeps_the_run_red(self) -> None:
         for other in (cf.CODE, cf.UNKNOWN):
             rerun, line = cf.rerun_decision(self.report([cf.MACHINE, other]), self.LATEST)